The invention relates to a device for pressing the adhesive-glued areas of continuously conveyed, flat objects, preferably the bottoms of flat-laying bags, by two dual belt conveyors running parallel to each other and mounted in a rack, and whose conveyor belts pressed against each other form pressing belts.
For example, in the production of bags from tubular sections of single or multiple layered paper, bottoms are tip-stretched onto both tubular section ends and, after the tubular section ends are drawn open, the bottoms are joined by overlapping folding and applying a glue layer and are closed by gluing a bottom cover sheet, if necessary after inserting a tubular valve. The bottoms are molded onto the tubular section ends while passing through a so-called bottom-laying station and are provided with layers of glue in the areas to be glued together. Before the bags produced in this way can be stacked or loaded onto palettes, the glued points have to set. For this purpose, the bags conveyed cross-laying pass through pressing stations in which pressing belts pressed against each other ensure good adhesive connections by pressing of the glued areas. Typical bottom-layers are designed such that they allow bottoms to be molded onto different size tubular sections in order to produce bags of different formats. According to the differently produced formats of the bags, in the pressing station downstream from the bottom-layer station the pressing belts"" distances must also be adjusted to the bottoms to be pressed. This arrangement, if at all possible, is typically connected with a costly conversion effort.
The technical problem of the invention is thus to create a device of the kind indicated in the beginning, in which the pressing belts can be quickly and easily adjusted to the glued areas to be pressed.
According to the invention, this technical problem is solved in that at least one dual belt conveyor is mounted on a support or frame that is guided cross-sliding in the rack.
The device according to the invention makes it possible to easily and quickly adjust the distance between the pressing belts to the glued areas to be pressed by simple sliding of at least one support or frame bearing a dual belt conveyor. As a rule, it should be sufficient to adjust only one frame bearing a dual belt conveyor, because the position of a bottom of a flat-laying bag is not changed and in case of a change in format, only the other bottom changes its distance.
According to a preferred form of construction, it is provided for that sliding blocks or slides are guided sliding on crossheads of the rack and bearing the support or frame with the dual belt conveyor.
The frame is usefully equipped with a drive for its parallel displacement, in such a way that the adjustment to different formats can be carried out by accordingly programmed control mechanisms.
The drive preferably consists of two spindles crossing the frame and on which spindle nuts are placed, and the spindles or spindle nuts mounted on the frame are equipped with synchronous drives.
According to a preferred form of construction, it is provided for that two spindles fixed on the rack cross the support or frame and spindle nuts mounted on the frame are driven by a continuous chain or belt drive via a gear motor.
In some cases it may be necessary for the other frame bearing the dual belt conveyor to be guided cross-sliding in the rack.
It is useful for this frame bearing the other dual belt conveyor to be detachably locked with the rack to be able to move it if necessary.
If the two frames bearing the dual belt conveyors are brought as closely together as possible, it may be necessary to still align them relative to the bags passing through, so that the pressing belts grasp in a favorable manner the glued bottoms to be pressed. The frame bearing the other dual belt conveyor is therefore preferably ablexe2x80x94after releasing the detachable lockingxe2x80x94to be connected with the first frame brought near it, such that both frames can be run through the drive together.
According to a preferred form of construction, it is provided that the locking consists of at least one two-arm lever mounted on the slide of the second frame with, at the lever""s ends, claws, one of which grips a bore or a notch of the guide of the slide, and that the lever is equipped with a swivel drive that swivels the lever to connect it to the first frame in such a way that while the first claw is released, the other claw grips into a bore or notch of the slide or a connecting part of the other frame. The drive swiveling the lever usefully consists of a pneumatic cylinder.